Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study.

BACKGROUND: The aim of this study is to conduct a comparative evaluation of different designs of clear aligners and examine the disparities between clear aligners and fixed appliances. METHODS: 3D digital models were created, consisting of a maxillary dentition without first premolars, maxilla, periodontal ligaments, attachments, micro-implant, 3D printed lingual retractor, brackets, archwire and clear aligner. The study involved the creation of five design models for clear aligner maxillary anterior internal retraction and one design model for fixed appliance maxillary anterior internal retraction, which were subsequently subjected to finite element analysis. These design models included: (1) Model C0 Control, (2) Model C1 Posterior Micro-implant, (3) Model C2 Anterior Micro-implant, (4) Model C3 Palatal Plate, (5) Model C4 Lingual Retractor, and (6) Model F0 Fixed Appliance. RESULTS: In the clear aligner models, a consistent pattern of tooth movement was observed. Notably, among all tested models, the modified clear aligner Model C3 exhibited the smallest differences in sagittal displacement of the crown-root of the central incisor, vertical displacement of the central incisor, sagittal displacement of the second premolar and second molar, as well as vertical displacement of posterior teeth. However, distinct variations in tooth movement trends were observed between the clear aligner models and the fixed appliance model. Furthermore, compared to the fixed appliance model, significant increases in tooth displacement were achieved with the use of clear aligner models. CONCLUSIONS: In the clear aligner models, the movement trend of the teeth remained consistent, but there were variations in the amount of tooth displacement. Overall, the Model C3 exhibited better torque control and provided greater protection for posterior anchorage teeth compared to the other four clear aligner models. On the other hand, the fixed appliance model provides superior anterior torque control and better protection of the posterior anchorage teeth compared to clear aligner models. The clear aligner approach and the fixed appliance approach still exhibit a disparity; nevertheless, this study offers a developmental direction and establishes a theoretical foundation for future non-invasive, aesthetically pleasing, comfortable, and efficient modalities of clear aligner treatment.

Association of interleukin-10-1082 (-1087) A > G polymorphisms and periodontitis risk: An updated meta-analysis based on 26 case-control studies.

BACKGROUND: The association between interleukin-10 (IL-10)-1082 (-1087) A > G polymorphism and either chronic (CP) or aggressive periodontitis (AgP) susceptibility was conflicting. This meta-analysis aimed to quantitatively estimate the association. METHODS: Pubmed, Embase, Web of Science, and WANFAN databases were searched for relevant studies that were submitted prior to January 31, 2018, and meta-analyses were performed using STATA 14.0. RESULTS: Database mining yielded 26 studies of interest. For the IL-10-1082 (-1087) A > G (rs1800896) polymorphism and its relation to CP susceptibility, the overall analysis showed no significant estimates, but subgroup analysis revealed significant associations in the AA versus GG + GA model in the Caucasian population (odds ratio [OR] = 1.274, 95% confidence interval [CI] = 1.069-1.518, P = 0.007; I2  = 0.0%, P = 0.483) and in the GG versus AA + AG model in the Han population (OR = 6.66, 95% CI = 7.72-9.41, P = 0.000; I2  = 0.0%, P = 0.82), which all showed no obvious publication bias by Egger's linear regression test. For the association between an IL-10-1082 (-1087) A > G polymorphism and AgP susceptibility, the overall analysis and Caucasian subgroup analysis yielded nonsignificant estimates. CONCLUSIONS: Our meta-analysis indicated that the IL-10-1082 (-1087) AA genotype in the Caucasian population, and the GG genotype in the Han population might be putative risk factors for CP. PRACTICAL IMPLICATIONS: The IL-10-1082 (-1087) AA genotype and the GG genotype might be potential biomarkers for Caucasian CP and for Han CP, respectively. However, additional research will be required to validate the findings of this meta-analysis.

Effects of Papacarie on children with dental caries in primary teeth: a systematic review and meta-analysis.

BACKGROUND: Caries in primary teeth hinder the child to bite and chew and influence their development. Papacarie has the characteristics of selective removal of decayed tissue and can preserve healthy dentine to the maximum, but its efficiency has not been critically evaluated compared to conventional method. AIM: This review is aiming at comparing the Papacarie and traditional method in caries removal in primary dental caries with children. DESIGN: Comprehensive literature searching at PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science to January 2018. RESULTS: Six randomized controlled trials (RCTs) and four prospective controlled clinical trials (CCTs) were included. The microbiota in caries dentine was significantly reduced using the Papacarie treatment (MD = 0.57, 95% CI 0.04 to 1.09, P = 0.03), and the anxiety feeling declined more in the Papacarie group (MD = -1.01, 95% CI -1.72 to -0.30, P < 0.005). There was a greater 200.79 (MD = 200.79, 95%CI 152.50 to 249.09, P < 0.00001) increase in time taken for the Papacarie treatment compared with the conventional method. CONCLUSION: Papacarie exerts a positive effect in reducing the bacteria and decreases the pain during caries removal in primary teeth although it costed a longer treatment time compared with the conventional method.

Evaluation of mandibular angle ostectomy using three-dimensional finite element analysis.

PURPOSE: This study was designed to investigate the stress and the displacement distributions of the mandible after mandibular angle ostectomy (MAO) by means of three-dimensional finite element analysis. METHODS: On the basis of a female patient with a prominent angle of the mandible, the finite element models were generated by helical computed tomography and related software and were analyzed under muscle forces and 3 kinds of biting conditions, including intercuspal position (ICP), incisal clenching (INC), and right unilateral molar clenching (RMOL). The mandibular stress and displacement distributions were analyzed by Abaqus software. RESULTS: In the model of MAO, the increased stress and the decreased displacement was found in ICP, INC, and RMOL at the area of mandibular angle. The stress and the displacement increased in ICP and RMOL, whereas the others remained unchanged in INC at the area of mandibular condylar neck. CONCLUSIONS: The results of this study have shown that MAO could alter biomechanical characteristics in the operated mandible, which suggested that a greater hit on face may lead to a higher incidence rate of condyle fracture and a lower incidence rate of angle fracture after MAO.

Osteogenesis response to implanted materials in endocortical bone in rat femora.

BACKGROUND: Orthopedic surgeons and dentists often implant materials to repair bone tissue defects and restore physiological functions of bone organs. The clinical success depends on adequate bone formation in operation sites. However, the real cause of osteogenesis has not yet been fully elucidated. To investigate the bone response to implanted materials, this study examined the bone tissue reaction in rat femoral medullary canal, which received gelatin and collagen as foreign-body materials. METHODS: A total of 36 six-month-old Sprague-Dawley rats were randomly and meanly divided into three groups. In the gelatin group, the bilateral femora received gelatin material; in the collagen group, they were implanted with type I collagen, and in the control group, the femora suffered from sham operation with no materials inserted. After 2, 4, 8, and 12 weeks, specimens were harvested and subjected to a series of examinations. RESULTS: After 2 weeks of healing, a significant upregulation of both alkaline phosphatase and osteocalcin by both kinds of implanted materials relative to the control (sham implantation group) was seen in gene expression analysis. Strong reactivity of osteoprotegerin and receptor activator of NFκB ligand was detected in the two test groups in immunohistochemistry at 4 weeks of healing. Also, micro-CT revealed an increase in cortical bone thickness in the two test groups as compared to the control group. Densitometry showed increased bone mineral density in the bone receiving materials after 12 weeks, leading to the enhanced maximum load in the test groups. CONCLUSIONS: These results indicated that the implanted materials led to an osteogenesis response in rat femoral medullary canal. Thus, we probably should reconsider the potential cascades of tissue reaction when utilizing orthopedic and dental implants and other materials to recover bone related-organ function and repair bone defects.

[Effect of low-intensity pulsed ultrasound on periodontitis in Beagle dogs].

OBJECTIVE: To investigate the effect of low intensity pulsed ultrasound (LIPUS) on periodontitis in Beagle dogs. METHODS: The animal model of chronic periodontitis was established with elastic ligature-induced alveolar bone defect in Beagle dogs. LIPUS with different intensity (50 mW/cm2, 100 mW/cm2) pulse wave and 50 mW/cm2 continuous wave, 1.5 MHz of frequency, 200 micros of pulse width modulated signal, and 1 kHz of repetition rate were applied to the dogs for 8 weeks (once a day and 20 minutes every time). The periodontal clinical examinations and histological biopsy were performed. RESULTS: With increased exposure to LIPUS, gum tissue swelling of the dogs was reduced. The plaque index (PLI), gingival index (GI), pocket depth (PD) of the treatment groups were lower than the control groups (P < 0.05). No significant gingival recession, attachment loss or furcation was found. The histological examination revealed that there was no obvious gingival hyperplasia in epithelial tissues, but there were significant activities in relation to collagen formation, decrease of bone resorption, and generation of active osteoblasts. CONCLUSION: LIPUS may help repair periodontal tissues and should be considered in guided tissue regeneration (GTR).

Two-stage treatment protocol for management of temporomandibular joint ankylosis with secondary deformities in adults: our institution's experience.

PURPOSE: Treatment of adult patients with temporomandibular joint (TMJ) ankylosis and secondary deformities is a challenging problem. Although various techniques, including arthroplasties, orthognathic surgery, autogenous bone graft, and distraction osteogenesis, have been described for the management of patients with this condition, an appropriate treatment protocol has not been established. The purpose of this report is to describe a 2-stage treatment protocol, comprising TMJ reconstruction as the initial surgery, followed by orthodontic treatment, and correction of secondary deformities as the second surgery, for the management of TMJ ankylosis with secondary deformities in adults. PATIENTS AND METHODS: From January 2003 to December 2009, 24 adult patients (30 joints) with TMJ ankylosis and secondary deformities underwent TMJ reconstruction as the initial surgery, followed by orthodontic treatment and correction of secondary deformities as the second surgery. Clinical outcome was assessed based on oral function, radiography, and medical photography. RESULTS: Patients were followed up for a minimum of 12 months to a maximum of 32 months (mean, 18.6 months). No relapse of TMJ ankylosis occurred in any patient during the follow-up period. Oral function and skeletal deformities were significantly improved in all patients. Satisfactory occlusion was achieved with the help of orthodontic treatment. Most of the patients were satisfied with the final outcome. CONCLUSIONS: The 2-stage treatment protocol described not only restores oral function but also improves the patient's esthetic appearance. We believe that it is a good approach for management of TMJ ankylosis with secondary deformities in adult patients.

Biomechanical analysis of reinstating buccally flared maxillary 2nd molars using 3D printing anchorage supports: a 3D finite element study.

The buccally flared maxillary 2nd molar has certain consequences on oral function and health. However, existing methods have some degree of disadvantages, such as invasion, complexity and side effects. The objectives of this study were to design anchorage systems to correct buccally flared maxillary 2nd molars and analyze their biomechanical effects by 3-dimensional (3D) finite element analysis. Finite element (FE) models of the 3D tanspalatal arches (TPAs) and 3D splints with different thicknesses and force points were constructed. The stress distribution on teeth, the hydrostatic pressure on periodontal ligaments and the initial displacement of teeth were analyzed. A total of 18 FE models were constructed and analyzed. The stress concentrated on a single anchorage tooth, and the hydrostatic pressure and initial displacement of the anchorage tooth were greater than those of the malposed 2nd molar in the 3D splint anchorage system. The stress spread on all anchorage teeth and the hydrostatic pressure and initial displacement of the anchorage tooth were less than those of the malposed 2nd molar in the 3D TPA anchorage system. Theoretically, the 3D TPA was better than the 3D splint as an anchorage to correct the buccally flared 2nd molar. A combination of 0.8 mm of thickness and mesial force point provided the optimal conditions for the 3D TPA. Further clinical studies should be conducted to verify the effects of 3D appliances.

Low-intensity Pulsed Ultrasound regulates alveolar bone homeostasis in experimental Periodontitis by diminishing Oxidative Stress.

Periodontitis is a widespread oral disease that results in the loss of alveolar bone. Low-intensity pulsed ultrasound (LIPUS), which is a new therapeutic option, promotes alveolar bone regeneration in periodontal bone injury models. This study investigated the protective effect of LIPUS on oxidative stress in periodontitis and the mechanism underlying this process. Methods: An experimental periodontitis model was induced by administering a ligature. Immunohistochemistry was performed to detect the expression levels of oxidative stress, osteogenic, and osteoclastogenic markers in vivo. Cell viability and osteogenic differentiation were analyzed using the Cell Counting Kit-8, alkaline phosphatase, and Alizarin Red staining assays. A reactive oxygen species assay kit, lipid peroxidation MDA assay kit, and western blotting were used to determine oxidative stress status in vitro. To verify the role of nuclear factor erythroid 2-related factor 2 (Nrf2), an oxidative regulator, during LIPUS treatment, the siRNA technique and Nrf2-/- mice were used. The PI3K/Akt inhibitor LY294002 was utilized to identify the effects of the PI3K-Akt/Nrf2 signaling pathway. Results: Alveolar bone resorption, which was experimentally induced by periodontitis in vivo, was alleviated by LIPUS via activation of Nrf2. Oxidative stress, induced via H2O2 treatment in vitro, inhibited cell viability and suppressed osteogenic differentiation. These effects were also alleviated by LIPUS treatment via Nrf2 activation. Nrf2 silencing blocked the antioxidant effect of LIPUS by diminishing heme oxygenase-1 expression. Nrf2-/- mice were susceptible to ligature-induced periodontitis, and the protective effect of LIPUS on alveolar bone dysfunction was weaker in these mice. Activation of Nrf2 by LIPUS was accompanied by activation of the PI3K/Akt pathway. The oxidative defense function of LIPUS was inhibited by exposure to LY294002 in vitro. Conclusions: These results demonstrated that LIPUS regulates alveolar bone homeostasis in periodontitis by attenuating oxidative stress via the regulation of PI3K-Akt/Nrf2 signaling. Thus, Nrf2 plays a pivotal role in the protective effect exerted by LIPUS against ligature-induced experimental periodontitis.

Low-intensity pulsed ultrasound upregulates osteogenesis under inflammatory conditions in periodontal ligament stem cells through unfolded protein response.

BACKGROUND: In periodontal tissue engineering, periodontal ligament stem cells derived from patients with periodontitis (P-PDLSCs) are among the most promising and accessible stem cells for repairing disrupted alveolar bone and other connective tissues around the teeth. However, the inflammatory environment influences the osteogenic differentiation ability of P-PDLSCs. We examined low-intensity pulsed ultrasound (LIPUS) in P-PDLSCs in vitro and in rats with experimental periodontitis to determine whether LIPUS can enhance the osteogenic differentiation of stem cells. MATERIALS AND METHODS: P-PDLSCs were harvested and isolated from the periodontal tissues around the teeth of periodontitis patients, and healthy PDLSCs (H-PDLSCs) were obtained from tissues around healthy teeth. After validation by flow cytometry analysis, the P-PDLSCs were cultured in osteogenic medium either pretreated with the endoplasmic reticulum stress (ERS) inhibitor 4-phenyl butyric acid (4-PBA) or not pretreated and then treated with or without LIPUS (90 mW/cm2, 1.5 MHz) for 30 min per day. Cell viability, ERS marker expression, and osteogenic potential were determined between the different treatment groups. LPS-induced H-PDLSCs were used to mimic the inflammatory environment. In addition, we established a model of experimental periodontitis in rats and used LIPUS and 4-PBA as treatment methods. Then, the maxillary bone was collected, and micro-CT and histology staining methods were used to detect the absorption of alveolar bone. RESULTS: Our data showed that the P-PDLSCs derived from periodontitis tissues were in a more pronounced ERS state than were the H-PDLSCs, which resulted in the former being associated with increased inflammation and decreased osteogenic ability. LIPUS can alleviate ERS and inflammation while increasing the bone formation capacity of P-PDLSCs in vivo and in vitro. CONCLUSIONS: LIPUS may be an effective method to enhance the outcome of periodontal tissue engineering treatments of periodontitis by suppressing inflammation and increasing the osteogenic differentiation of P-PDLSCs through the unfolded protein response pathway, and more detailed studies are needed in the future.

Effects of periodontal endoscopy on the treatment of periodontitis: A systematic review and meta-analysis.

BACKGROUND: For this systematic review, the authors evaluated and synthesized the available scientific evidence related to the effects of periodontal endoscopy on the treatment of periodontitis. METHODS: The authors searched PubMed, Embase, Cochrane Library, Chinese Scientific Journals database, China National Knowledge Infrastructure, and Chinese Medicine Premier's Wanfang database for articles about periodontal endoscopy that were published through January 2017. The authors considered the percentage of residual calculus, average treatment time, bleeding on probing (BOP), gingival inflammation (GI), and probing depth (PD) as outcome measures. The authors extracted data and performed meta-analyses for groups of articles for which it was appropriate. RESULTS: The authors identified 8 articles as being suitable for this systematic review. The investigators of 3 studies reported results related to BOP and GI that revealed some advantages of periodontal endoscopy over traditional scaling and root planing (SRP). The investigators of 4 studies explored PD and found no difference between periodontal endoscopy and traditional SRP. The authors could not perform meta-analyses on the study results related to BOP, GI, or PD. The percentage of residual calculus after periodontal endoscope-aided debridement was significantly less than the percentage of residual calculus after traditional SRP (mean difference, -3.18; 95% confidence interval, -4.86 to -1.49; P = .002; heterogeneity I2 = 74%). The authors found that periodontal endoscopy took significantly more time than traditional SRP (mean difference, 6.01 minutes; 95% confidence interval, 4.23 to 7.8; P < .00001; heterogeneity I2 = 0%). CONCLUSIONS AND PRACTICAL IMPLICATIONS: Periodontal endoscopy may provide additional benefits for calculus removal compared with traditional SRP, although it could take more time to perform. With respect to BOP, GI, and PD, the authors found no sufficient evidence to support the difference between the use of periodontal endoscopy and traditional SRP. The authors concluded that additional scientific research is required to assess the effects of periodontal endoscopy on the treatment of periodontitis.

Submucosal injection of dexamethasone reduces postoperative discomfort after third-molar extraction: A systematic review and meta-analysis.

BACKGROUND: The authors conducted a systematic review and meta-analysis on the effect of dexamethasone (DX) on edema, trismus, and pain during early and late postoperative periods after third-molar (M3) extraction. TYPES OF STUDIES REVIEWED: The authors identified eligible reports by searching PubMed, Embase, and the Cochrane Central Register of Controlled Trials up through April 2016. The full text of the studies that met the minimum inclusion requirements were those in which the investigators evaluated the effects of submucosal injection of DX compared with inactive treatments in patients undergoing surgical extraction of an M3. RESULTS: The authors included 11 eligible trials in this study. Participants receiving DX had significantly less edema during both early (standardized mean difference, 3.28; 95% confidence interval [CI], 2.21-4.36; P < .00001) and late (standardized mean difference, 0.56; 95% CI, 0.27-0.86; P < .00001) periods after surgery, as well as less trismus than did control participants during the early (standardized mean difference, 5.34; 95% CI, 2.44-8.24; P = .004) phase, but there was no strong evidence for the reduction of trismus in the late period. Because of heterogeneity in intervention and outcome assessments across the studies, the authors only qualitatively summarized pain outcomes. CONCLUSIONS AND PRACTICAL IMPLICATIONS: The findings of this study suggest that submucosal injection of DX reduced not only early and late edema but also early trismus in experimental compared with control participants after M3 extraction, which makes it a likely choice for dental clinical use. However, larger and higher-quality trials are needed to guard against bias to confirm the effect in late trismus and pain.

TrAmplification of Human Dental Follicle Cells by piggyBac Transposon - Mediated Reversible Immortalization System.

Dental follicle cells (DFCs) are the precursor cells of periodontium. Under certain differentiation conditions, DFCs can be induced to differentiate into chondrogenic, osteogenic and adipogenic cells. However, DFCs has limited lifespan in vitro, so it's difficult to harvest enough cells for basic research and translational application. pMPH86 is a piggyBac transposon-mediated vector which contains SV40 T-Ag cassette that can be removed by flippase recognition target (FRT) recombinase. Here we demonstrated the pMPH86 can effectively amplify human DFCs through reversible immortalization. The immortalized DFCs (iDFCs) exhibit higher proliferate activity, which can be reversed to its original level before immortalization when deimmortalized by FLP recombinase. The iDFCs and deimmortalized DFCs (dDFCs) express most DFC markers and maintain multiple differentiation potential in vitro as they can be induced by BMP9 to differentiate into chondrogenic, osteogenic and adipogenic cells evidenced by gene expression and protein marker. We also proved telomerase activity of iDFCs are significantly increased and maintained at a high level, while the telomerase activity of primary DFCs was relatively low and decreased with every passage. After SV40 T-Ag was removed to deimmortalize the cells, telomerase activity was reduced to its original level before immortalization and decreased with passages just the same as primary DFCs. These results suggest that piggyBac immortalization system could be a potential strategy to amplify primary cells, which is critical for regenerative research and further clinical application.

Retrospective comparison of autogenous cosotochondral graft and coronoid process graft in the management of unilateral ankylosis of the temporomandibular joint in adults.

We retrospectively compared the clinical outcomes of autogenous coronoid process grafts (n=32) and costochondral grafts (n=28) in condylar reconstruction for the treatment of unilateral ankylosis of the temporomandibular joint (TMJ) in adults. Preoperative and postoperative assessments included diet scores, cone-beam computed tomography (CT), maximal interincisal opening, lateral excursion, and mandibular deviation on opening the mouth. There were no significant differences between the 2 groups in the measurements before and after the operation with respect to incisal opening, lateral excursion, mandibular deviation, diet scores, or recurrence rate, but in both the postoperative incisal opening, lateral excursion, and diet scores had improved significantly compared with preoperatively. After costochondral graft 3 patients developed intraoperative plural tears, and 6 had temporary pain at the donor site. The frontal branch of the facial nerve was temporarily affected in 5 patients after costochondral graft and 3 after coronoid process grafts, all of which recovered in 3-6 months. There was no recurrence after coronoid process grafting, and one after costochondral grafting. The clinical outcomes in both groups were satisfactory and comparable. Autogenous coronoid process grafting may therefore be a good alternative for condylar reconstruction in patients with ankylosis of the TMJ.

Effect of different doses of transforming growth factor-ß1 on cartilage and subchondral bone in osteoarthritic temporomandibular joints.

Transforming growth factor-beta (TGF-ß) plays an important part in the repair of cartilage in osteoarthritis. It has been hypothesised that intra-articular injection of TGF-ß1 promotes repair of cartilage and protects the subchondral bone from damage in osteoarthritic temporomandibular joints (TMJs). We made bilateral partial perforations of the disc to induce osteoarthritic joints in 36 rabbits. TGF-ß1 20, 40, or 80 ng were injected into the right joint, and vehicle alone was injected into the left joint. Four additional animals were used as normal controls. Microcomputed tomography was used to quantify the three-dimensional microarchitecture of subchondral bone, followed by assessment of the proteoglycan content. All joints treated with TGF-ß1 were covered by a layer of well-organised fibrocartilage, and had increased proteoglycan content and normal microarchitectural properties, whereas the joint treated by vehicle alone had typical osteoarthritis-related degradation of cartilage and sclerosis of subchondral bone. These results suggested that TGF-ß1 is an effective way of treating osteoarthritis of the TMJ.

Correction of mandibular deficiency by inverted-L osteotomy of ramus and iliac crest bone grafting.

This study was to describe the use of inverted-L osteotomy of ramus and iliac bone graft for the management of mandibular deficiency in adult patients. From 2008 to 2010, 11 patients (aged 19 to 29 years) with mandibular deficiency underwent intraoral or extraoral inverted-L osteotomy of ramus and iliac crest bone grafting. Data were collected from the patients' records, photographs and radiographs. The height and width of the ramus were successfully expanded by inverted-L osteotomy and iliac crest bone grafting with minimal complications in all patients, resulting in significant improvement in occlusion and facial appearance. Our early results showed that the inverted-L osteotomy of ramus and iliac crest bone grafting is safe and effective, and should be considered as a good alternative for the patients with mandibular deficiency.

Changes in quality of life after orthognathic surgery: a comparison based on the involvement of the occlusion.

OBJECTIVES: The aims of this study were to investigate the impact of dentofacial deformities on quality of life in Chinese patients and to make a comparison between facial deformities that do and do not involve the occlusion. STUDY DESIGN: Consecutive patients with dentofacial deformities requiring surgical correction were divided into 2 groups. Group A represented those who had undergone presurgical orthodontic treatment, and group B represented patients with square faces or prominent zygoma. All subjects were assessed by the 36-item Short-Form Health Survey (SF-36) and the 22-item Orthognathic Quality of Life Questionnaire (OQLQ-22) during 2 time periods: preoperatively and 6-8 months postoperatively. RESULTS: The SF-36 revealed that there was significant difference in role physical and bodily pain (P < .05) preoperatively between the 2 groups, whereas postoperatively the difference was not significant. Preoperatively, there was significant difference in oral function and facial esthetics components of OQLQ (P < .001), whereas postoperatively only the oral function domain showed significant difference. CONCLUSIONS: Orthognathic surgery had a positive impact on patients' quality of life regardless of the type of deformity. OQLQ showed better discerning ability and was able to point out the subtle differences between the 2 groups.

[Narrowing and sliding genioplasty procedure combined with mandibular outer cortex ostectomy technique to correct square jaw in short face].

OBJECTIVE: To evaluate the the feasibility and effectiveness of narrowing and sliding genioplasty combined with mandibular outer cortex ostectomy technique to reshape a square jaw in short face. METHODS: From July 2005 to October 2009, a total of 57 patients received narrowing and sliding genioplasty combined with mandibular outer cortex ostectomy procedure to correct square jaw in short face. All the patients had standard frontal and lateral cephalometric radiographs, panoramic radiographs, and were photographed preoperatively and postoperatively to assess their face contour. The alteration of mandibular angle, mental contour and width of lower face was observed for 6 to 24 months postoperatively. Questionnaires were used to assess the patients' satisfactory. RESULTS: It showed that the postoperative lower face had narrowed and become softer, slender and oval, with a slick mental region. The final aesthetic outcomes were quite satisfactory in all cases from both the view of surgeons and patients. CONCLUSIONS: Narrowing and sliding genioplasty combined with mandibular outer cortex ostectomy procedure could efficiently adjust the shape and position of chin to obtain a good proportion of the lower face, and to change square and short face to slender oval one by single operation in accordance with the fashionable aesthetics in orientals.

Strontium ranelate treatment enhances hydroxyapatite-coated titanium screws fixation in osteoporotic rats.

Increased bone turnover with excessive bone resorption and decreased bone formation is known to impair implant fixation. Strontium ranelate is well known as an effective antiosteoporotic agent by its dual effect of antiresorbing and bone-forming activity. This study was designed to evaluate the effect of systemic strontium ranelate (SR) treatment on fixation of hydroxyapatite (HA)-coated titanium screws in ovariectomized (OVX) rats. Twelve weeks after being OVX (n=30) or sham (n=10) operated, 40 female Sprague-Dawley rats received unilateral implants in the proximal tibiae. The OVX rats were randomly divided into the following groups: OVX, OVX+SRL ("L" refers to low SR dose of 500 mg/kg/day), OVX+SRH ("H" refers to high SR dose of 1000 mg/kg/day).Twelve weeks after treatment, bone blocks with implants were evaluated with micro-CT and biomechanical push-out tests. Compared to OVX animals, SR treatment increased the bone volume ratio by 51.5% and 1.1-fold, the percentage osteointegration by 1.0-fold and 1.9-fold in micro-CT evaluation, and the maximal force by 1.9-fold and 3.3-fold in biomechanical push-out test, for the low and high dose of SR, respectively. Significant correlation between micro-CT and biomechanical properties demonstrated that trabecular parameters played an important role in predicting the biomechanical properties of implant fixation. Our findings suggest that SR treatment can dose-dependently improve HA-coated screw fixation in OVX rats and facilitate the stability of the implant in the osteoporotic bone.